High-time-resolution wide-energy-region X-ray spectrum quantitative measurement system and method

Abstract

The invention discloses a high-time-resolution wide-energy-region X-ray spectrum quantitative measurement system and method. The high-time-resolution wide-energy-region X-ray spectrum quantitative measurement system and method have the beneficial effects that quantitative diagnosis of wide-energy-region (0.2 keV-5. 0keV) and high-time-resolution (lt, 40ps) X spectrum is realized by combining a height pair transmission type grating (TG), an X-ray streak camera (XSC) and a flat response radiation flow detector (FXRD), and the time resolution of the system is superior to that of an existing soft X-ray energy spectrometer (-200ps). Compared with an existing time-resolved transmission grating spectrometer, the system realizes quantitative measurement of the wide-energy-region X-ray spectrum intensity evolution process.

Description

Technical Field

[0001] This invention relates to the field of high energy density physics, specifically to a high time-resolution wide-energy-range X-ray spectroscopy quantitative measurement system and method. Background Technology

[0002] In inertial confinement fusion, laboratory astrophysics, and other high-energy-density physics research, the X-ray spectral evolution characteristics of plasma emission can reflect important information such as the internal temperature and equilibrium of the plasma. In high-energy-density physics systems, the state of laser plasma changes rapidly over time (on the order of tens to hundreds of ps), and the X-ray spectral coverage is wide (from hundreds of eV to several keV), with the spectral structure exhibiting rapid evolution characteristics. Achieving quantitative measurements of X-ray spectra with a wide energy range, high spectral resolution, and high time resolution is of great significance for in-depth exploration of the plasma state evolution characteristics in high-energy-density physics systems.

[0003] In existing technologies, the Dante spectrometer employs multiple channels (~10) to measure X-ray radiation flux in different energy regions. Its X-ray spectral measurement range can cover the energy range from tens of eV to several keV, or even tens of keV, and can be used to measure time-varying X-ray spectra over a wide energy range. However, limited by the spectrometer's spectral measurement principle, its spectral resolution is insufficient, and its time resolution is on the order of hundreds of ps, making it difficult to fully meet the diagnostic needs for the X-ray spectral evolution characteristics of rapidly evolving plasmas.

[0004] Time-resolved transmission grating spectrometers based on X-ray streak cameras and transmission gratings are important tools for achieving wide-energy-range (hundreds of eV to several keV), high time resolution (tens of ps), and high spectral resolution (E / ΔE ~ 20@200 eV) X-ray spectral measurements. However, the diffraction characteristics of transmission gratings result in significant differences in the intensity of dispersive signals between the high-energy and low-energy regions of the diffraction spectrum, easily exceeding the dynamic range of the X-ray streak camera. Furthermore, the X-ray streak camera involves a complex series of conversions and electron transport processes, including X-ray-electron, electron multiplication, and electron-visible light, making sensitivity calibration of the entire system extremely complex. Moreover, the sensitivity of X-ray streak cameras is highly sensitive to operating voltage, and offline static calibration conditions differ from online measurement conditions, making quantitative measurement of X-ray streak cameras difficult. Therefore, in fields such as ICF black cavity energy and radiation-matter interactions, quantitative measurement of wide-energy-range X-ray spectra using time-resolved transmission grating spectrometers remains challenging. Summary of the Invention

[0005] In view of this, one of the objectives of the present invention is to provide a high time-resolution, wide-energy-range X-ray spectral quantitative measurement system that can achieve wide-energy-range, high time-resolution, and high spectral-resolution X-ray spectral quantitative measurement, solving the problem of rapid-changing X-ray spectral quantitative diagnosis in the field of high-energy-density physics.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A high time-resolution wide-energy-range X-ray spectroscopy quantitative measurement system is characterized by including a support frame assembly on which three sets of measurement channels are mounted. The middle measurement channel is composed of a time-resolved transmission grating spectrometer, and the two side measurement channels are each composed of a flat-response radiation flow detector. The extension directions of the center lines of the three sets of measurement channels can converge at a point so that the line of sight of the three measurement channels can be simultaneously aligned with the X-ray source to be measured.

[0008] The time-resolved transmission grating spectrometer includes a channel housing, a transmission grating is installed in the middle of the channel housing, and an X-ray stripe camera is installed at the rear end. The X-ray stripe camera has an X-ray stripe camera photocathode inside. The transmission grating and the X-ray stripe camera photocathode are arranged perpendicularly, and the height of the center line of the transmission grating is flush with the height of the center line of the X-ray stripe camera photocathode.

[0009] Preferably, the angle between each of the flat-response radiation flow detectors and the time-resolved transmission grating spectrometer is less than 6°.

[0010] Preferably, the X-ray stripe camera uses a width-gradient Au photocathode.

[0011] Preferably, the period of the transmission grating is 0.3 μm.

[0012] Preferably, a neutral attenuator is provided at the front end of the channel housing of the time-resolved transmission grating spectrometer.

[0013] Preferably, the flat-response radiation flow detector is adjustablely mounted on the side of the support frame assembly via an angle adjustment mechanism.

[0014] The second objective of this invention is to provide a high-time-resolution, wide-energy-range X-ray spectroscopy quantitative measurement method, characterized by comprising the following steps:

[0015] S1: Set up the X-ray spectral quantitative measurement system according to any one of claims 1-6, and adjust the angles of the three sets of measurement channels until the extension directions of the center lines of the three sets of measurement channels intersect at one point; then arrange a gold ball at the intersection of the extension directions of the center lines of the three sets of measurement channels, and irradiate the gold ball with eight lasers to generate an X-ray source;

[0016] S2: Measure the time-resolved X-ray spectral image using the time-resolved transmission grating spectrometer, and obtain the time-resolved X-ray spectral distribution by spectral interpretation. ;

[0017] S3: The X-ray radiation flux intensities measured using the two flat-response radiation flux detectors are respectively and The intensity of the X-ray radiation flux emitted by the radiation source under test toward the location of the time-resolved transmission grating spectrometer is obtained as follows: ;

[0018] S4: For a given time, the energy spectrum integral of the X-ray spectral intensity distribution measured by the time-resolved transmission grating spectrometer is equal to the radiation flux entering the spectrometer, i.e.

[0019] ,

[0020] In the above formula, The quantitative coefficients for X-ray spectroscopy can be obtained by reverse calculation. The intensity-quantified X-ray spectrum was obtained as follows: .

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. The high time-resolution, wide-energy-range X-ray spectroscopy quantitative measurement system provided by this invention employs dedicated FXRD channels on both sides of a time-resolution transmission grating spectrometer to achieve near-coaxial measurement arrangement. By utilizing the FXRD to obtain the time evolution curve of radiation flux intensity from the energy spectrum integration, and combining it with the high time-resolution, wide-energy-range X-ray spectral relative intensity distribution measurement results from the transmission grating spectrometer, the quantitative challenge of X-ray spectral evolution diagnosis is overcome. This also solves the problem that complex X-ray streak camera overall response calibration and offline calibration results are difficult to apply to online measurements.

[0023] 2. The high time-resolution, wide-energy-range X-ray spectroscopy quantitative measurement method provided by this invention combines a high-line-pair transmission grating (TG), an X-ray streak camera (XSC), and a flat-response radiation current detector (FXRD) to achieve quantitative diagnosis of wide-energy-range (0.2keV~5.0keV) X-ray spectra with high time resolution (<40ps). Its time resolution is superior to existing soft X-ray spectrometers (~200ps). Compared with existing time-resolution transmission grating spectrometers, this system achieves quantitative measurement of the intensity evolution process of wide-energy-range X-ray spectra. Attached Figure Description

[0024] Figure 1 A schematic diagram of a high time-resolution, wide-energy-range X-ray spectroscopy quantitative measurement system;

[0025] Figure 2 A schematic diagram of an embodiment of a high time-resolution, wide-energy-range X-ray spectroscopy quantitative measurement system;

[0026] Figure 3 Measured X-ray spectra with time resolution;

[0027] Figure 4 The intensity of X-ray radiation flow is measured by two flat-response radiation flow detectors 7. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0029] A high-time-resolution, wide-energy-range X-ray spectroscopy quantitative measurement system is provided, capable of simultaneously achieving time-resolved and intensity-quantitative X-ray spectroscopy measurements. For example... Figure 1 and Figure 2 As shown, the system includes a support frame assembly B, on which three sets of measurement channels are mounted. The middle measurement channel consists of a time-resolved transmission grating spectrometer A, while the two side measurement channels each consist of a flat-response radiation current detector 7. The support frame assembly B allows the two flat-response radiation current detectors 7 to be mounted approximately coaxially on both sides of the time-resolved transmission grating spectrometer A. The extension directions of the centerlines of the three measurement channels can converge at a point, so that the line of sight of the three measurement channels can be simultaneously aligned with the X-ray source under test. The flat-response radiation current detector 7 is also known as an FXRD. The time-resolved transmission grating spectrometer A includes a channel housing A1, with a transmission grating 5 mounted in the middle of the channel housing A1 and an X-ray fringe camera 6 mounted at the rear end. That is, the transmission grating 5 and the X-ray fringe camera 6 constitute the time-resolved transmission grating spectrometer channel. The X-ray stripe camera 6 has an X-ray stripe camera photocathode 61 built in. The transmission grating 5 is arranged perpendicular to the X-ray stripe camera photocathode 61, and the height of the center line of the transmission grating 5 is the same as the height of the center line of the X-ray stripe camera photocathode 61. That is, the center lines of the transmission grating 5 and the X-ray stripe camera photocathode 61 coincide with the center line of the channel housing A1, which is an equal height coincident installation arrangement.

[0030] In this embodiment, the angle between each flat-response radiation flow detector 7 and the time-resolved transmission grating spectrometer A is less than 6°, in order to reduce the field-of-view difference between the FXRD and the time-resolved transmission grating spectrometer A, and ensure that the X-ray radiation flow intensity measured by the two flat-response radiation flow detectors 7 is accurate. and Consistent within the experimental error range.

[0031] In this embodiment, the flat response radiation flow detector 7 is adjustablely mounted on the side of the support frame assembly B via an angle adjustment mechanism, thereby ensuring the accuracy of the installation angle of the flat response radiation flow detector 7.

[0032] Based on the above-mentioned X-ray spectroscopy quantitative measurement system, the high time-resolution wide-energy-range X-ray spectroscopy quantitative measurement method is as follows, including the following steps:

[0033] S1: Set up the X-ray spectroscopy quantitative measurement system and adjust the angles of the three sets of measurement channels until the extension directions of the center lines of the three sets of measurement channels intersect at one point; then place the gold ball 2 at the intersection of the extension directions of the center lines of the three sets of measurement channels, and use eight-way laser 1 to irradiate the gold ball 2 to generate X-ray source 3;

[0034] S2: Measure the time-resolved X-ray spectral image using the time-resolved transmission grating spectrometer A, and obtain the time-resolved X-ray spectral distribution through spectral interpretation. ;

[0035] S3: The X-ray radiation flux intensities measured using two flat-response radiation flux detectors 7 are respectively and The intensity of the X-ray radiation flux emitted by the radiation source under test toward the location of the time-resolved transmission grating spectrometer A is calculated as follows: ;

[0036] S4: For a given moment, the energy spectrum integral of the X-ray spectral intensity distribution measured by the time-resolved transmission grating spectrometer A is equal to the radiation flux entering the spectrometer, i.e.

[0037] ,

[0038] In the above formula, The quantitative coefficient for X-ray spectroscopy is obtained from the above experiments. , and By working backward, we can solve for... The intensity-quantified X-ray spectrum was obtained as follows: .

[0039] The advantage of this system lies in the dedicated FXRD channels on both sides of the time-resolved transmission grating spectrometer A, enabling near-coaxial measurement arrangement. By utilizing the FXRD to obtain the time evolution curve of the radiation flux intensity from the energy spectrum integration, and combining it with the high time-resolved, wide-energy-range X-ray spectral relative intensity distribution measurement results from the transmission grating spectrometer, the system overcomes the quantitative challenge of X-ray spectral evolution diagnosis and solves the problem of applying complex X-ray streak camera overall response calibration and offline calibration results to online measurements.

[0040] Next, taking the energy spectrum measurement of an X-ray source generated by laser irradiation of a gold sphere using a time-resolved transmission grating spectrometer A as an example, we will utilize the high time-resolved wide-energy-range X-ray spectral quantitative measurement system proposed in this invention to simultaneously obtain time-resolved spectral images and X-ray radiation flux data. The radiation flux measured by the two FXRD channels is consistent within the experimental error range, meeting the design requirement that the field of view difference of the three channels is negligible.

[0041] Step S1, please refer to Figure 2An X-ray source 3 is generated by irradiating a gold sphere 2 with a diameter of 400 μm with an eight-channel laser 1. The wavelength of the eight-channel laser 1 is 351 nm, the energy of a single laser beam is ~400 J, the focal spot size is 500 μm in diameter, and the laser pulse width is ~1 ns square wave.

[0042] Step S2: Install the entire system onto the target chamber, ensuring that the intersection of the line of sight of the time-resolved transmission grating spectrometer A and the flat-response radiation current detector 7 coincides at the X-ray source 3. The transmission grating 5 is placed vertically, and the photocathode 61 of the X-ray streak camera is placed horizontally. In this embodiment, the X-ray streak camera 6 uses a second-gradient width Au photocathode to modulate the intensity difference between the high-energy and low-energy regions of the diffraction spectrum of the transmission grating 5, reducing the dynamic range requirements of the X-ray streak camera 6. A neutral density filter 4 is provided at the front end of the channel housing A1 of the time-resolved transmission grating spectrometer A.

[0043] Step S3: The time-resolved diffraction spectrum is measured using a time-resolved transmission grating spectrometer A. X-ray radiation passes through a neutral density filter 4 and is incident on the transmission grating 5. The transmission grating 5 disperses X-rays of different energies to different positions along the length of the photocathode 61 of the X-ray streak camera according to the grating diffraction equation. Under the scanning of the X-ray streak camera 6, a time-resolved X-ray spectral image is obtained, as shown below. Figure 3 As shown. Among them, the X-ray fringe camera 6 adopts a 5ns scan rate to achieve high temporal resolution (<40ps). At the same time, it adopts a variable width Au cathode to effectively reduce the signal intensity difference between the high energy region and the low energy region. The period of the transmission grating 5 is 0.3μm, achieving high spectral resolution (E / ΔE ~ 20@200eV).

[0044] Step S4: Based on the time-resolved X-ray spectral image obtained in step S3, interpret the spectrum to obtain the relative intensity of the time-resolved energy spectrum. .

[0045] Step S5: The time evolution curve of X-ray radiation intensity is measured using two flat-response radiation flow detectors 7. and . refer to Figure 4 The radiation flux curves measured by the two flat-response radiation flux detectors 7 are consistent within the error range. The time-resolved transmission grating spectrometer A is located between the two flat-response radiation flux detectors 7, and the X-ray radiation flux intensity within its field of view lies between the measured values ​​of the two detectors. Therefore, the X-ray radiation flux within the field of view of the time-resolved transmission grating spectrometer A is... .

[0046] Step S6: For a given time, the energy spectrum integral of the X-ray spectral intensity distribution measured by the time-resolved transmission grating spectrometer A is equal to the total radiation flux entering the time-resolved transmission grating spectrometer A, i.e. By combining the measurement results from the flat-response radiation current detector 7 and the time-resolved transmission grating spectrometer A, the quantitative coefficients of the X-ray spectrum are solved. This allows us to obtain a quantitative time-resolved X-ray energy spectrum. .

[0047] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A high temporal resolution, wide energy range, X-ray spectroscopy quantitative measurement system, characterized by, The X-ray spectrum quantitative measurement system comprises a support frame assembly (B) on which three groups of measurement channels are installed, wherein the middle measurement channel is composed of a time-resolved transmission grating spectrometer (A), and each of the two side measurement channels is composed of a flat response radiation flow detector (7), the extension directions of the center lines of the three groups of measurement channels can converge at one point, so that the three measurement channels can simultaneously aim at the X-ray light source to be measured; The time-resolved transmission grating spectrometer (A) comprises a channel housing (A1), a transmission grating (5) is installed in the middle of the channel housing (A1), and an X-ray streak camera (6) is installed at the rear end, the X-ray streak camera (6) is internally provided with an X-ray streak camera photocathode (61), the transmission grating (5) and the X-ray streak camera photocathode (61) are arranged vertically, and the height positions of the center lines of the transmission grating (5) and the X-ray streak camera photocathode (61) are flush.

2. The high time resolution, broad energy range X-ray spectroscopic quantitative measurement system of claim 1, wherein: The included angles between each flat response radiation flow detector (7) and the time-resolved transmission grating spectrometer (A) are less than 6°.

3. The high time resolution, broad energy range X-ray spectroscopic quantitative measurement system of claim 1, wherein: The X-ray streak camera (6) adopts a width twice-varying Au photocathode.

4. The high time resolution, broad energy range X-ray spectroscopic quantitative measurement system of claim 1, wherein: The transmission grating (5) has a period of 0.3 μm.

5. The high temporal resolution, broad energy range, X-ray spectroscopic quantitative measurement system of claim 1, wherein: The front end of the channel housing (A1) of the time-resolved transmission grating spectrometer (A) is provided with a neutral attenuation sheet (4).

6. The high temporal resolution, broad energy range, X-ray spectroscopic quantitative measurement system of claim 1, wherein: The flat response radiation flow detector (7) is adjustably installed on the side of the support frame assembly (B) through an angle adjusting mechanism.

7. A method of high temporal resolution, wide energy range X-ray spectroscopy quantitative measurement, characterized by, The method comprises the following steps: S1: erecting the X-ray spectrum quantitative measurement system according to any one of claims 1-6, adjusting the angles of the three groups of measurement channels until the extension directions of the center lines of the three groups of measurement channels converge at one point, then arranging a gold ball (2) at the intersection point of the extension directions of the center lines of the three groups of measurement channels, and irradiating the gold ball (2) with eight laser beams (1) to generate an X-ray light source (3); S2: measuring a time-resolved X-ray spectral image using the time- resolved transmission grating spectrometer (A), and obtaining a time- resolved X-ray spectral distribution by spectral decomposition ; S3: The X-ray radiation flux intensity measured by the two said flat response radiation flux detectors (7) is respectively and , and the X-ray radiation flux intensity emitted by the radiation source to be measured to the position where the time-resolved transmission grating spectrometer (A) is located is ; S4: for a given moment, the energy spectrum integral of the X-ray spectrum intensity distribution measured by the time-resolved transmission grating spectrometer (A) is equal to the radiation flow entering the spectrometer, ， In the above formula, is the X-ray spectrum quantification coefficient, and according to the back calculation, the following can be solved , and the intensity quantified X-ray spectrum is .

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